JPS6156364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of grouting using non-consolidating materials.

When injecting grout, it is commonly used to use the drilling rod as it is as an injection pipe. However, when the injected grout hardens, it forms a strong solid around the rod, tightening the rod. Therefore, the rod must be constantly rotated during injection to break the adhesion. However, as the drilling depth increases, a boring machine with greater rotational force and pulling force is required, but this also has its limits and is a cause of various troubles at the site.

Here, this type of grout injection method will be explained in advance with reference to drawings. Fig. 1 shows a first conventional example. and casing pipe 52.
(for example 3m). Next, a sealing member 53 made of rubber or the like is provided at the entrance of the insertion hole 51 of the concrete body 50, and a caulking material 54 is provided between the insertion hole 51 and the casing pipe 52 (Figure a). Next, as shown in Figure b, a drilling rod 55 that also serves as an injection pipe is fitted with a metal bit at the tip.
is inserted into the casing pipe 52, a pre-bender 56 is installed on the inlet side, and a hole is drilled to a predetermined depth while jetting water from the drilling rod 55 and rotating the rod 55 itself. At this time, the slime passes around the rod 55 and overflows to the inlet side, so it is discharged through the flow path 57. Once this drilling has been completed, the distance from the imaginary line R in the same figure (for example,
1m) After finishing the rod 55, grout 58
is pumped through the rod 55 and injected into the surrounding ground. When the injection is completed, the injection hose (not shown) and the inside of the rod 55 are washed with water, and the grout 58 is filled with water.
Wait for it to harden (about 10 minutes). If the rod 55 is left too long in the drilled hole, the rod 55 will be fixed by the hardened grout 58', so the rod 55 is retreated to the mouth of the casing pipe 52 as shown in Fig. c. Next, as shown in Figure d, when a solidified body of hardened grout 58' is formed in the step just performed, the drilling rod 55 is reinserted and the same hole as described above is drilled in the next step. , and then perform the next injection.

However, as can be inferred from the above explanation, this method requires a lot of work, such as retracting the rod to the mouth and drilling the hole again in order to avoid the rod from sticking. If the depth becomes deeper, there is a limit to how much the rod can be rotated or pulled out.

Figure 2 shows the second conventional example.
As shown in the figure, a relatively long (for example, 3 to 9 m) casing pipe 60 is installed, and then a hole is drilled to a predetermined depth using a drilling rod 61. Next, an injection tube consisting of a double tube equipped with a packer 62 at the tip, which is separate from the drilling rod 61, is installed inside the casing pipe 60, and the B liquid is injected from the inner tube 63 into the inner tube 63 and the outer tube 64. Liquid A is pumped through the gap and injected into the first stage (Figure b). In the following, drilling and injection of the next stage are performed sequentially in the same manner.

FIG. 3 shows an example of deeper injection, in which a longer casing pipe 65 is provided inside the casing pipe 60 and the same construction as the second conventional example is performed. Figure 4 shows an example of a deeper case.
Similar construction is performed by providing a third casing pipe 66.

In the examples shown in FIGS. 2 to 4, the drilling rod and the injection pipe are separate bodies, and a double-pipe injection pipe can be used, so a two-shot method with a short gel time can be adopted. However, drilling holes for inserting the casing pipe, erecting the casing pipe, and injecting the caulking material are time-consuming, and the seal may not function sufficiently, causing leakage and making it difficult to pull out the injection pipe. Furthermore, there is another problem in that the casing pipe becomes an obstacle during tunnel excavation and must be cut before excavation. Moreover, the amount of casing pipe used is large, making it uneconomical.

The present invention solves the above-mentioned conventional problems at once, and fills a non-consolidating material into a hole-drilling rod that also serves as an injection pipe or between the injection pipe and a drilled hole, thereby preventing grouting into the rod or injection pipe. The purpose is to prevent adhesion, thereby making it easier to rotate and pull out, thereby improving the speed and economy of construction.

The inventor initially thought that the method shown in FIG. 5 would be sufficient to achieve the object, and conducted preliminary experiments. First, after forming a concrete body 1 on the target ground, an insertion hole 2 is bored and a casing pipe 3 is inserted. A space between the casing pipe 3 and the insertion hole 2 is filled with a caulking material 4, and a sealing material 5 such as rubber is provided. Next, a drilling rod 6 which also serves as a double-pipe injection pipe is inserted into the casing pipe 3, and a preventer 7 is attached. In this way, the rod 6 is rotated while drilling to a predetermined depth. When this is finished, the inside of the drilled hole is washed with water and slime etc. are discharged from the discharge path 6a. Next, a non-consolidating material 8, which will be described later, is injected through the rod 6 to fill the space between the rod 6 and the drilled hole. After the water permeability test is completed, the rod 6 is moved back slightly, liquids A and B are pumped into the rod 6, and grout 9 is injected from the tip, completing one stage of injection. The rod 6 is kept in that position even when the grout 9 hardens. In the next stage, the hole is drilled deeper by the rod 6, filled with non-consolidating material, etc., and injected with grout in the same manner as in the above-mentioned operations. The same construction is then repeated in sequence.

Here, the non-consolidating material 8 may be any material that does not consolidate, does not flow away when grout is injected, and does not react with grout, for example, barite (mainly containing barium sulfate) in bentonite mud ) was preferred.

When the area around the rod 6 is filled with this non-consolidating material 8, even if the grout 9 hardens, the rod 6 is edged by the non-consolidating material 8. It does not stick and the first
Unlike the conventional example, there is no need to retreat the rod 6 to the entrance, and even if drilling to the next stage is started after the grout 9 has hardened, the rotational force can be small.

However, although there are the above-mentioned advantages, on the other hand, the grout liquid blows out from inside the drilled hole, and sufficient penetration cannot be achieved.

6 and 7 illustrate the present invention. That is, as shown in FIG. 7, a groove (for example, 150 cm in length) 11 is formed in the peripheral wall of the distal end of the injection tube/hole-drilling rod 10, and a groove made of a flexible material such as rubber is formed in the groove 11. Cylindrical police car 12
The upper and lower parts are baked and fixed. A communicating hole 13 is formed in the peripheral wall of the rod 10 in the intermediate portion. In addition, inside the rod 10, although the details are not shown, there are formed a liquid A path, a liquid B path, a packer flow path, and a flow path through which a non-consolidating material passes if necessary, and the outlet of the packer flow path serves as a communication hole 13. put.

Thus, first, as shown in Fig. 6a, after inserting the casing pipe 3 in the same manner as in the preliminary experiment,
The rod 10 is used to drill a hole to a predetermined depth. Next, after washing the inside of the drilled hole with water, the non-consolidating material 8 is flowed out and filled around the rod 10 as shown in Fig. b. Thereafter, the rod 6 is moved back a little, water or air is pumped from the inlet side through the packer flow path, and the pressure causes the central part of the packer 12 to expand and press against the hole wall. In this state, grout 9 consisting of liquid A and liquid B is pumped and injected into the surrounding ground. When the injection is completed, the pumping of water is stopped, the packer 12 is uninflated, and the packer 12 is housed in the groove 11 again as a cylindrical packer 12. After waiting for the grout 9 to harden, drilling begins again in the same way for the next stage, and in the next stage, after filling with the non-consolidating material 8, etc., the grout is injected (c figure).

By adopting such a method, it is possible to perform smooth injection while preventing an increase in rotational force due to adhesion of grout gel and preventing grout from entering the inlet side.

In addition, the present invention uses both the injection pipe and the drilling rod to sequentially repeat drilling and injection, which is economical since there is no need to replace the drilling rod and the injection pipe. However, if this is a sacrifice, the drilling rod and the injection pipe may be separate bodies, or the injection may be performed by drilling a hole in advance with the drilling rod and then inserting the injection pipe. Further, in the present invention in which a packer is used, since the packer holds the borehole wall, there is no need to use a casing pipe.

By the way, the present inventors carried out the following construction on the ground at a certain location. In other words, first, a rotary and percution combination drilling machine was used to drill 33.3m.
Drill a hole to a depth of
A non-caking material (hereinafter referred to as a liquid barrier) adjusted to a concentration of 1.3 was injected and allowed to leak from the preventer, and when the liquid became thick, the pot was closed to form a liquid barrier around the rod.

Grout was then injected into the surrounding ground at a pressure of 75 Kg/cm ² . The amount of injection was 1,780, and the grout used was a suspension type, made of water glass and cement milk, and had a gel time of 7 minutes. After that, water was supplied while waiting for the grout to take effect, and the next step drilling work could be carried out in 10 minutes.

As a result of this construction work, the following advantages were found.

Rotation of the rod is not required during grouting.

When water was sent through the rod, the concentrated liquid barrier from the preventer immediately flowed out to the inlet side, and 10 minutes later, the next drilling operation could be started. In this point,
According to the method of retracting the rod to the mouth and re-drilling the hole as in the preliminary experiment, during that time,
Although it took about 2 hours, it was found that the workability was significantly improved.

In the conventional method, the water pressure is 80 to 100 to push the grout around the rod toward the inlet.
Although it takes Kg/cm ² , the method of the present invention allows the liquid barrier to be smoothly extruded at about 40 Kg/cm ² .

This prevents grout from penetrating into the previously poured zone, which is often the case with conventional rod injection.

The liquid barrier did not react with the grout at all, and no change in the properties of the injected grout was observed.

As described above, according to the present invention, since the area around the drilling rod or injection pipe is filled with a non-consolidating material, there is no sticking due to grout, and the rotation and extraction of the rod or injection pipe is extremely easy. The advantages are extremely large, especially when performing injection deep into the ground. In addition, so-called jamming, in which the drilling rod cannot rotate, can be reliably prevented. Since only a small rotational torque is required by the drilling machine, problems such as equipment damage and inability to rotate are eliminated. Furthermore, it is economical since there is no need to use complicated construction methods and expensive casing pipes as in the conventional example.

[Brief explanation of the drawing]

Figures 1 a to d, Figures 2 a and b, Figures 3 and 4 are sectional views showing conventional examples, Figures 5 a to c are sectional views showing preliminary experimental examples, and Figures 6 a to 4. c is a sectional view showing the second invention construction method, and FIG. 7 is an enlarged sectional view of the main part of the tip of the rod. 1... Concrete body, 2... Insertion hole, 3...
Casing pipe, 4...Caulking material, 5...
Sealing material, 6...Drilling rod that also serves as injection pipe, 6a...
...Discharge channel, 7... Preventer, 8... Non-consolidating material, 9... Grout, 10... Drilling rod that also serves as injection pipe, 11... Concave groove, 12... Packer, 1
3...Communication hole.

Claims (1)

[Claims] 1. A flexible packer is wrapped around the peripheral wall of the tip of the rod, and the packer is made inflatable by fluid pressure pumped from the entrance side of the hole to drill the target ground to a predetermined depth. and then discharging a non-consolidating material through the rod to fill the periphery of the rod,
The packer is then expanded and grout is injected through said rod, and after the injected grout has hardened, the hole is drilled to the next step, filling with the above-mentioned non-consolidating material, expanding the packer and injecting the grout. Characteristic grout injection method. 2. The flexible packer is cylindrical and is wrapped in a groove formed in the peripheral wall of the tip of the rod, and returns to its cylindrical shape when fluid pressure is removed. grout injection method. 3. The grout injection method according to claim 1, wherein the non-consolidating material is pentonite mud with an additive containing barium sulfate as a main component.